Fill the Bottom of Your Large Planter (35 Best Ideas)

Score!

You found a ganga deal at the garden store. A beautiful (and bargain-basement cheap) extra large outdoor planter. You wrestled it home and now you’re wondering:

“What can I use to fill the bottom of a large planter?”

Because, fill it you must.

Well, you’re in luck ~ you have lotsa’ options!

In this article, you’ll find 35 cost-effective “large pot” filler ideas. And, to make your wallet even happier, you can probably find many of these fillers around your home.

So, read on to learn:

  • Why you’d want to use a filler in your large planter,
  • What you need to consider before filling your large planter,
  • Why use light fillers,
  • When to use heavy fillers ~ and, finally,
  • Some tips to successfully use fillers in the bottom of your large container.

Beware, there are different opinions in the gardening community about using fillers in the bottom of large planters. Should you really use them? And if so, what should you use? A lot of people ask, “Can you put styrofoam in the bottom of a planter?” and “What about pine cones in the bottom of a planter?” I’ll address all those questions and more ~ so you can make an informed decision.

Ready? Let’s get started!

First up,

Why use fillers in the bottom of a large planter?

old wood deck board that could be from damage caused by heavy planters

Well, the main reason you want to use fillers is to take up space and allow good drainage.

Other reasons to use fillers are:

  • Soil is expensive.
    • Adding filler means you need less soil…
    • Which means, you save money.
  • Soil is heavy.
    • Using all soil makes a large planter heavy and difficult to move.
    • Heavy loads can cause damage to decks or balconies over time.
    • Adding filler allows you to lighten the load, so to speak.
  • Soil compresses under its own weight.
    • Compression can cause soil to compact and affect how well the soil drains.
    • When soil compacts around roots, it impairs root growth.
    • Adding filler helps you improve soil drainage and encourage healthy roots.
  • And finally, using fillers in the bottom of your extra large planters for outside helps the environment by keeping non-biodegradable products out of the landfills. Win-win!

heavy or light bottom FILLER: what does your large planter need?

large wood planters in field overlooking water that might use filler in the bottom to make them heavy

There are two things to consider before choosing your filler.

First, do you have large flower pots that you want to…

  • hang,
  • move, or
  • locate in a spot where weight might be an issue ~ such as on a balcony or an old deck?

If so, you would want a light filler.

Or, do you have a large planter box that you actually want to be heavy? Perhaps, tall outdoor planters that…

  • will stay in one place permanently,
  • might need to be stabilized to avoid accidental knock-overs, or
  • is located in a spot where theft is possible.

If those are your thoughts, you want a heavy filler.

Keep it light, baby! bottom fillers that lighten the load.

plastic water bottle similar to what could be used to fill the bottom of a large planter lying on sand near the surf

I know, I know, I promised not to overwhelm you with massive lists. Analysis paralysis ~ and all that.

But, I want to give you enough ideas on what to put in planters other than plants or dirt so you can use what you have on hand. To keep it manageable, I organized the fillers into 7 categories. So, here goes.

Light materials you can use to fill the bottom of your large planter include:

  1. Recycled plastics
    1. Water/soda bottles
    2. Water or milk jugs (lids on, if possible)
    3. Solo cups (turned upside down)
    4. Take-out plastic food containers
    5. Empty detergent bottles
    6. Nursery pots and 6-packs (turned upside down)
    7. Unused plastic pots (turned upside down)
  1. Recycled foam materials
    1. Packing peanuts (make sure they’re not the dissolvable kind!)
    2. Styrofoam blocks/packing materials (yes! you can put styrofoam in the bottom of a planter!)
    3. Take-out foam containers
    4. Craft balls (pricey)
    5. Blocks from the floral section of a craft store (pricey)
  1. Other creative fillers from “around the house”
    1. Aluminum/soda cans (crushed or uncrushed, your choice)
    2. Old swimming pool noodles
    3. Plastic Easter eggs (emptied and clean, of course!)
    4. Plastic colander (cheap at The Dollar store ~ and it already has holes for drainage)
  1. Organic materials
    1. Sphagnum moss
    2. Coconut fiber
    3. Mulch leaves
    4. Pine cones (good for soil conditioner, too)
    5. Small tree branches & sticks
    6. Recycled cardboard and newspaper

Some people prefer commercial fillers to fill the bottom of their large planters, so here are 3 lightweight commercial fillers that are available at most home improvement stores, garden centers, or Amazon.com. (Full disclosure, I have’t used any of these products but they all have good reviews.)

  1. Lightweight Commercial fillers
    1. Better than Rocks
    2. Packing Pearls
    3. Ups A Daisy

drop anchor! bottom fillers to weigh your planter down.

broken and unbroken clay pots lying in rows on their sides perfect for using as filler in the bottom of a large planter

Heavy materials you can use to fill the bottom of your large planters include:

  1. Non-organic materials (won’t break down)
    1. Gravel
    2. Pea pebbles
    3. Landscape/river rock (big and small)
    4. Old ceramic tiles (intact or broken)
    5. Broken pieces of pottery
    6. Bricks
    7. Cinderblocks
  1. Organic materials (will break down over time)
    1. Wood logs
    2. Big tree branches
    3. Sharp, gritty sand

Tips, Tricks & things to keep in mind when deciding to fill your large planter.

3 clay planter pots showing bottom hole with dirt spilled out and tools nearby

7 tips to make filling the bottom of your extra large planter a success:

  1. Make sure to have at least one drainage hole in the bottom of your large planter to avoid stagnant water. Otherwise bacteria and mold can develop. Some people place a sponge in the bottom of their planter to absorb extra moisture (and prevent dirt from falling out the drainage hole). If your large plant pots and trough planters don’t have a drainage hole, Kevin at Epic Gardening shows how to DIY.

  1. Only fill your container 1/4 to 1/3 of the way from the bottom of the planter with your chosen “filler” (or even a combination of fillers). You want room to add enough soil for a good root system.

  1. Form a barrier between your filler and the soil. You can cut a piece of plastic screen such as soft window screening, a piece of mesh, or some landscape/weed barrier fabric big enough to fit into your container. Place this on top of the filler. This keeps the soil in place and prevents dirt from sliding down into your filler material.

  1. If you use packing peanuts, contain them in a non-biodegradable material such as an old pair of pantyhose or nylon stocking. This avoids a “packing peanut” mess when you eventually empty your planter.

  1. If you have space, keep the styrofoam blocks used to securely package electronics and cut them down as needed. Then you’ll always have material on hand to fill the bottom of your large planter.

  1. Consider placing the top on any water bottles and jugs to prevent water from collecting in them. Again, think mold and bacteria.

  1. Make sure your filler is healthy for whatever you’re planting in your large container, especially if they’re edibles such as herbs or vegetables. You can double-check at your local nursery or gardening store if you have any questions.

To Fill or Not to Fill…

island in body of water in shape of question mark

And finally, like so many things in life, people have different thoughts about what to use to fill the bottom of a large planter.

  • Horticultural purists say roots need all the room they can get and recommend using good quality soil only.
  • Some gardeners caution against using sand as a filler; it can create an undesirable sandy soil mix.
  • Other gardeners say “don’t use anything biodegradable” such as newspapers, cardboard or paper cups.
  • And even others recommend avoiding natural organic materials such as leaves, coconut fiber, sphagnum moss, pine cones, sticks, tree limbs, etc. What’s their objection? Organic and biodegradable materials break down and can mix with the soil so eventually your “filler” doesn’t do its job.
  • Gardeners on the other side of the fence (yep, pun intended) will tell you that biodegradable material improves soil through natural composting. Even most newspaper print is now plant-based and safe for composting. And they use it as filler ~ with good results.

What this means is:

  • if you’re planting annuals in your large planter and decide to use an organic or biodegradable filler such as pine cones in the bottom of your planter, you may notice some (minimal) breakdown. But your filler should last the whole season.
  • If you’re planting perennials, your organic filler will eventually break down and you’ll have to add more soil or replace your filler every couple of years. (And if you need ideas on perennials that grow well in shade, check out this related post.)

My advice: Use what you have available.

so, how do you fill the bottom of a large planter?

multi-colored Big Sale sign that might get somebody a super deal on a large planter that needs filling

There you have it.

35 things you can use to fill the bottom of a large planter. 35 different materials you can use to either make your large container light and moveable ~ or heavy and stable. 35 alternatives that will help you save on soil when filling your large planter.

Bottom line: You have 35 options that can help save you money.

Making your ganga deal a REAL steal!

So now ~ head on out to the garden and start filling your beautiful (and bargain-basement cheap) planter!

To your gardening health!

9 thoughts on “Fill the Bottom of Your Large Planter (35 Best Ideas)”

  1. Thanks for the ideas!
    I just emptied a large planter that I had on my back patio (the plants were very tired) and was agonizing over how much soil I needed to re-plant for the fall. Curiously, I happen to have a large piece of styrofoam in my garage that was destined for trash pickup at the end of the week. Now, it’ll be repurposed and save me some $$$ too.
    Your article came to the rescue! Thank You!

    Reply
  2. I have a large section of solar pool cover. It looks like bubble wrap and much more durable. I plan to try that in several large planters.

    Reply
  3. Thank you for this! I’ve just begun a plant ministry – taking plant starts and supplies to nursing homes and the like for people to pot their own plants. Fun? Yes! Exciting? Absolutely! Appreciated? Humbly so. Expensive to provide enough soil to fill all the pots (especially for larger plants)? You bet!
    This is a great help in continuing the ministry at a rate I can afford. Thank you, you’re a God-send!

    Reply
  4. I live in a very windy place and have tall planters. Has anyone tried the basketball gel that holds portable basketball goals in place? Would that work?

    Reply
  5. I am going to do the large galvanized 6x2x2 planters on my deck. Of the 2 feet of depth, how much should be filler vs dirt? 6 inches of filler so I have about a foot or so of soil to plant?

    Reply

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